Method of forming piston rings



1811- 1944. v. F. ZAHODIAKIN METHOD OF FORMING,PISTON RINGS Filed Oct.17, 1940 //v VEN TOR By ;W@ M MA 7' TOR/VEVS Patented Jan. 18, '1944UNITED STATES PATENT OFFICE 2,339,588 METHOD OF FORMING PISTON RINGSVictor F. Zahodiakin, Maplewood, N. J. v Application October 17, 1940,Serial No. 361,484

Claims.

bustion engines but is not limited to thi use.

It is capable of use, with the same advantages, as the oil ring for thepistons of pumps, steam engines or any installation where it isnecessary to prevent the escape of oil along the cylinder wall past thepiston.

The ring disclosed in the aforesaid co-pending application is formedfrom a single strip of metal to provide a structure embodying box-likeor U- shaped segments open to the side facing the cylinder wall andhaving perforated back walls. Thus, in radial cross-section, therespective segments appear U-shaped. The sections are integrallyconnected by spring loops, which loops are disposed between the top andbottom walls of the ring, thereby forming spacers and supports uponwhich the walls are supported as the loops flex The advantages of thistype of ring are fully set forth in the co-pending application.

It has been the object of the inventor in this application to provide amethod of constructing the improved piston ring, whereby it is made froma single strip of metal in an extremely sim-.

pl manner by forming the basic structure of the complete ring in punchpress or stamping operations and thereafter completing the ring bybending operations performed on this basic structure.

It ha been the broad object of this inventor to provide a method offorming the ring, which method utilizes the simple operations ofpunching and bending, the die constructions being of the utmostsimplicity and the ring resulting from the method steps being accuratelyformed and uniform in all of its dimensions Other advantages or theinvention will be more fully apparent from the description of thedrawing in which:

Figure l is a top plan view of a strip of metal,

showing the portions thereof in various stages of formation culminatingin the complete ring structure at the right-hand end.

Figure 2 is a general view looking at th side edge of the strip showingit passing through the various mechanisms performing th method steps.

Figure 3 is a sectional view taken on line 3-3, Figure 2, detailing thedie which removes certain of the metal prior to the bending operationsFigure 4 is a sectional view taken on line 4-4,

Figure 2, illustrating the loop forming die in .de tail. 1 y

Figure 5 is a sectional view taken on line 5-5,

Figure 2, illustrating in detail the bending dies.

which form the top and bottom walls of the respective segments of thering.

Figure 6 is a view taken similar to Figure 5 but illustrating the die ofFigure 5 in its advanced position wherein the walls are formed. 7

Referring to the drawing, a flat strip of metal, I0 is fed into the dieand bending mechanisms by means of a feeding mechanism (not shown). Thestrip passes between elements H and I2 and is gripped after each advanceby a holding finger l3. This holding finger I3 is swung on a pivot 14 bypressure applied at its lower or outer end [5 for gripping the stripagainst the upper element Il,as at I6. 1

The strip passes .over a punching table or platen H. A punch indicatedat l8, cooperating with an aperture 19 in the table, forms the oilclearance apertures 20. Each time the strip pauses, this punch descendsto punch a hole.

On the next advance of the strip, assuming that this is the first holeto be formed, a pilot pin 2| engages the opening 20 and indexes with thebore 22 in the table.

Th next operation is performed by means of a set of four dies 23. These.dies cooperate with bores 24 in the table and are effective for forminga'series of small holes in rectangular relationship about the respectiveapertures 20. These apertures 25 define the corners of the cut-outportions of the metal, that is to say, that portion of the metal lyingwithin a zone defined by a line drawn between the adjacent apertures ofadjacentsets and extended from these apertures to the sides of thestrip. The purpos of formin or defining these corners is to preventbunching or folding of the metal in the corners as the metal removingdies operate. The next operation is performed upon the strip by means ofmetal removing dies 26 .of which there are a pair operating in dove-tailslots 21 in th respective side edges of the, table. These dies descendupon the strip, particularly that area defined hereto fore, for removingthe metal as illustrated. These notch portions provide edges 28 flaredinwardly toward each other toward the outer edges of the strip.

Now as to this group of mechanisms, it will be noted that alter thepilot pin descends, three die erally in this operation by means of apair of dies 30, 3|, male and female respectively. These die elementsoperate upon the narrow portion 32 of the metal left after the cut outportions are removed. Thus the portions 33 which are to constitute thetop and bottom walls of the ring segments are drawn close together intosubstantial abutment with their edges 29-29 slightly spaced.

In the next operation, the strip is engaged between a pair of dies 34,35, male and female respectively. These dies are shown in Figures 5 and6, and turn the portions 33 at right angles to the portions 32. Thus thebox-like segments are completed.

In the next operation, the loops 29 are engaged by means of dies or thewall portions 33 and effective for gripping and forming the loops. Thesedies provide arouate forming ends thereby pressing the loops intosemi-circular form. At the same time as the loops are drawn together,the ring is formed into generally circular form as indicated generallyat 31. It will be noted at this time that the edges 28 of the notchedout portions are moved into positions where they are radially disposedrelative to the center of the ring and are very minutely spaced.

The loop completing mechanism is generally indicated at 38 and includesthe dies or fingers 36 operated bymeans of a ram 39 carrying a roller40. The roller engages inclined surfaces 4| of the fingers 36. Theseinclined portions face each other and flare inwardly so-the roller iseffective in spreading the outer ends of the finger and clamping theinner ends of the fingers together as the ram moves in. A coil spring 42under tension between pins 43 adjacent the ram is effective forspreading the fingers when theram retreats.

When the strip passes beyond the dies 30, 3! it is obvious that thelongitudinal feed of the strip still being in the same stages as before,that is equal to the distances between the punch l8 and the pilot pin2!, a different timing for the dies 34, 35 and 38, 36 will be required.These dies will act oftener and their operations will be synchronizedwith the operations of the rest of the dies. In order to accommodate forinaccuracies ln-timing, a certain amount of slack is provided betweenthe dies 30, 3| and dies 34, 35, and between dies 34, 35 and dies 36.36. Also the device 38 is fed into and out of the strip as a unit inorder to clear the preceding and next succeeding loops.

Thus the finished ring provides segments, U- shapedor box-like in form,consisting of the back walls, 44 and top and bottom walls 33 with anaperture 20 in the back wall of each. These sections are connected bythe loops 29 and provide the necessary flexibility for the ring Theedges 28 of'the sections are. disposed relatively close together onradial lines and thus the ring is free fingers 36 operating between i toflex with the minute spacing preventing loss of oil between thesections.

Having described my invention, I claim:

1. A method of forming a piston ring from a strip of metal comprisingthe steps oi; punching the metal of the strip to provide segmentsconnected by narrow strips; bending said narrow strips to provide openthroated loops at right angles to the strip; bending the laterallyextended portions of the segments toward each other and in parallelismin position overlying and engaging the ends of the loops therebysubstantially closing the throats of the loops and drawing the U-shapedportions of the strip closer together;

bending the strip into circular form with the loops projected radiallyoutwardly.

2. A method of forming a piston ring consisting of the steps of; forminga strip of metal to provide a blank having laterally adjacent notchesalong its respective edges; forming the strip portions intermediaterespective laterally adjacent notches into open throated loops; bendingthe portions of metal lying between the notches along each edge of thestrip toward each other into position overlying the loops to formU-shaped sections; compressing the strip on itself lineally to close thethroats of the loops; bending the strip into circular form with theU-shaped sections facing outwardly in thefinished ring and the loopsextending radially outwardly between the upper and lower walls of theU-shaped sections.

3. The method of forming a piston ring consisting of the steps of;punching a strip of metal to provide a narrow central strip havinglaterally extended adjacent portions converging outwardly; bending thecentral strip between the laterally adjacent portions at right angles tothe strip to form substantially open throated loops; bending thelaterally adjacent portions upon the loops to provide U-shaped portionsbetween the loops; substantially closing the throats of the loops andthereby-drawing the U-shaped portions of the strip closer together and;thereafter bending the ring into generally circular form with theadjacent edges of the laterally extended portions disposed on radiallines and minutely spaced.

4. The method of forming a piston ring from I,

a strip of metal comprising the steps of; punching apertures in saidstrip at spaced points; punching sets of apertures in rectangulararrangement around said first named apertures, the apertures in saidsets on each side of the first named apertures being equally spaced fromthe strip edge; removing the metal within the spaces defined by linesrunning between those longitudinally aligned apertures of the adjacentsets and from these longitudinally aligned apertures to the adacent sideedges of the strip to form a series of narrow central strips havingsubstantially parallel edges; forming said narrow strips into loops;forming the wide portions of the strip into U- shaped segments openingoutwardly in the finished ring and including as their inner walls ineach instance a portion of the metal having one of the first namedapertures therein and; bending the strip into circular form with theloops and U-shaped segments projected radially outwardly.

5. The method of forming a piston ring from a strip of metalcomprisingthe steps of punching sets of apertures in said strip in spacedrelationship to delineate pairs of spaced notches in correspondingposition on the two sides of the strip, each pair of correspondingnotches being separated laterally by a narrow central strip; removingthe metal from the notch portions so defined; bending the interiorstrips at right angles to the main strip to form open throated loops,bending the wide portions of the strip between the notches into U-shapedsegments overlying the loops; compressing the strip lineally to closethe throats of the loops and into close juxtaposition and; thereafterbending the strip into circular form with the loops and U-shapedsegments projected radially outwardly.

- VICTOR F. ZAHODIAKIN.

to bring the U-shaped segments

